The present invention relates to a fuel supply pump for use in an internal combustion engine including a tappet guide structure for preventing a pivotal movement of a tappet.
As a tappet guide structure for preventing a pivotal movement of a tappet of a fuel supply pump used in an internal combustion engine such as a diesel engine, a configuration disclosed in JP-A-5-195907 or JP-A-2004-204761 has been known.
JP-A-5-195907 discloses that in order to prevent the circumferential pivotal movement of the tappet which reciprocates in a cylinder hole formed inside a pump housing of the fuel supply pump in an axial direction, a positioning tappet guide groove which is parallel to the axial direction is disposed on an inner peripheral surface of the cylinder hole, a slider protruding in a direction perpendicular to an axis of the cylinder hole is formed in the tappet, and the protruding slider is configured to reciprocate in the tappet guide groove, thereby preventing the pivotal movement of the tappet.
As a configuration for preventing the circumferential pivotal movement of the tappet which reciprocates in the cylinder hole formed inside the pump housing of the fuel supply pump in the axial direction, JP-A-2004-163816 discloses a configuration for preventing the pivotal movement of the tappet by disposing a slit-shaped through-hole on a side wall of the tappet, causing a guide pin to pass through the through-hole from outside of the pump housing, and using a tip portion of the guide pin to guide the slit-shaped through-hole of the tappet.